The locals flee and, left to their own devices, a gaggle of cheerful lunatics escape the asylum and take over the town — thoroughly confusing the lone Scottish soldier who has been dispatched to defuse the bomb.

The retreating Germans wire the automaton clock in the main square to set off a bomb when the mechanical knight strikes the bell at midnight, blowing up the ammunition magazine and the entire town.

The barber is killed while transmitting to the Allies, only managing to relay that the magazine will blow up when “the knight strikes at midnight.” Signaller Charles Plumpick, whose expertise is caring for war pigeons, not explosives, is sent by his colonel to disarm the bomb.

He needs to discover the meaning of the phrase “the knight strikes at midnight.” Arriving in town with two pigeons in a cage, Plumpick must evade German soldiers.

Back in town, Plumpick is knocked unconscious by a falling pole, unaware when the inmates leave the asylum, occupy the town, and take on the roles of the townspeople, including those of bishop, brothel madame, prostitutes, barber, circus manager, circus performers, firefighters, soldiers, duke, and duchess.

The barber, his supposed contact, does not recognize the password phrase “the mackerel likes frying" and is unhelpful to Plumpick’s mission.

Despite his protests, they take their "king," bound and gagged, to a balcony overlooking the square to watch as the British and German troops confront and shoot each other dead.

It was paired with Marv Newland's Bambi Meets Godzilla and John Magnuson's Thank You Mask Man and marketed under the heading The King of Hearts and His Loyal Short Subjects.

The cast featured Don Scardino as the lead character, who was reworked as an American soldier named Johnny Perkins.